it's a pretty straight forward process. Gangs and single parameters are equal entities when it comes to patching controllers to them. It actually makes no or little sense to patch a controller to a gang and another controller to a gang member….
Gangs are groups of parameters…simply.
Don't overlap, don't patch too many controllers to parameters, write things down..and in case you get lost, use CLEAR SETUP to reinit the unit system to factory defaults.
Learn this forever: an assignment is ONLY wiped if you re_edit it exactly as it was originally created…and change controller or null it. Gangs don't wipe out single parameters patches and the opposite is also true.
Time to get some rest….